nitrogen fixation

nitrogen fixation defined in 1951 year

nitrogen fixation - nitrogen fixation;nitrogen fixation - Conversion of atmospheric nitrogen into organic nitrogen compounds, a process that can be carried out only by certain soil-inhabiting bacteria and certain blue-green algae (Cyanophyta). Some nitrogen-fixing bacteria live symbiotic-ally with leguminous plants (peas, beans, clover, etc.) in nodules on roots, others live independently in soil. By their activity soil is enriched in nitrogen, a fact of considerable practical importance. See also: Nitrogen Cycle.